Singleton broke the game open with a grand slam in the second, giving Fresno a 9-2 lead with his 10th home run of the season, this one off pitcher Tyler Matzek.
An inning later, Singleton drilled a two-run homer, his 11th, to center field. Just like that, he'd racked up eight RBIs in three innings.
In the fifth, Singleton missed an opportunity to pad his RBI total when he struck out with runners at second and third. After he added two more in the top of the sixth on a single to left field, he had a chance to tie the modern-day Pacific Coast League record of 11 in his final at-bat, but he lined out to right field to lead off the top of the ninth.
Singleton has now driven in 35 runs over 32 games for the Grizzlies. He leads the Minors in homers and RBIs, taking over the lead from another Fresno slugger, Preston Tucker, who was No. 1 in both categories despite being promoted to Houston a week ago.
The Grizzlies are represented by three players atop the Minor League RBI leader board. Houston's No. 1 prospect, Carlos Correa, joined Fresno on Tuesday and is tied for second in the Minors, at 32, with Tucker and Peter O'Brien of Reno (D-backs). Correa went 1-for-4 with two walks and three runs scored on Wednesday night.
Singleton's grand slam was his second in three games, during which he went 7-for-12 with four homers and 18 RBIs. In his past nine games, he has seven round trippers and 25 RBIs.
After signing a five-year deal with three club options last season, Singleton hit .168/.285/.335 with 13 homers and 44 RBIs in 95 games for the Astros.